"Most lawyers that I speak to dismiss Twitter as yet another plaything for their children. Of what possible relevance, they inquire, could this possibly be for a senior legal practitioner?" writes Professor Richard Susskind in the new introduction to his highly regarded book The End of Lawyers?, which was published in paperback last week.

"I reply that I know quite a few general counsel and senior in-house lawyers who now use Twitter and regularly send out messages about what they are doing, what they are thinking, and where they are going; and if my clients were sending out regular updates on their news and views, I would want to be on the receiving end, even if the medium has a slightly silly name."

The legal IT and strategy guru's endorsement alone is enough for many lawyers, but further persuasive evidence of the growing power of Twitter in the legal world comes in a newly published survey of in-house lawyers in the US. They are increasingly using blogs and social media to keep informed of legal and business developments; but while 76 of the top US 100 firms have a presence on Twitter, the survey found that just under half of them have not tweeted once.

However, many in-house lawyers are aware of Twitter and a significant minority of younger ones are using it regularly. The survey said 26% of those aged 30-39 agree that a law firm's prominence on Twitter will influence whether they are instructed. It predicted that Twitter's influence could increase substantially over the coming years.

I agree. I was a sceptic when I joined Twitter earlier this year for the launch of my own website @legalfutures. It just seemed like something I had to do, but I have become increasingly convinced by its value. This comes in many forms: spreading awareness of my site, making contact with people with similar interests, and being pointed to people and information that I otherwise might not have found (such as the above survey). It's not perfect by any means – some people can tweet you to distraction – but I also like the sense of community.

I asked fellow legal tweeters for their views last week. Given the comments above about in-house lawyers, interestingly there was a rapid response from that community. @in_house_lawyer said it had provided real-time access to legal developments, a better network and enabled her to carve out a niche. @jcasalmir said that through Twitter she had met people she would like to emulate in her in-house practice. Fellow American @changesq said Twitter "reveals the 'human' side of fellow lawyers and execs, helping to develop camaraderie online & off".

Others, such as immigration law blogger @freemvntblog, talked about the access to legal updates, @catrinmills said it had helped her land a deal with a legal publisher, and there was perhaps unsurprisingly a good response from younger lawyers. @arc7 said he was about to start his law conversion course – "Twitter has given me access to lawyers and blogs which have influenced my thinking" as well as "people who have been happy to answer my questions". @kevinpoulter said it had helped the Law Society's junior lawyers division communicate with its members, while on a personal level he had maintained and built peer-to-peer relationships "and occasionally client relationships".

The role of Twitter has also been the subject of debate on the Law Society Gazette's LinkedIn group over the past week (another interesting business tool), and it has exposed some of the concerns lawyers have – what kind of persona law firms should present (perhaps the most extreme is Scottish firm Inksters, where every solicitor and trainee is encouraged to tweet), what kind of information should be shared and what precisely the value is.

But those who are really keen are keen for a reason – because they have seen benefits, whether directly in terms of work, or indirectly in terms of knowledge and contacts. Well-known legal public relations specialist @clarerodway told me that it can be more than just profile-raising – it can be used for "extremely targeted prospecting" for clients. "Lawyers ask, 'Can social networking win business?' The A is in the Q: It's a social NETWORK so as useful as any other networking," she said. In fact, she continued in a second tweet, it can be better than networking in the real world because "you can work a roomful of relevant people without leaving your desk."

But Twitter has its dangers too. @Jooge_DeCaux – also starting his law conversion course – said Twitter convinced him to do law in the first place. "If I fail @charonqc, @blawgreview, @taxbod et al owe me £14k."